Java ConcurrentLinkedDeque addAll()用法及代码示例

ConcurrentLinkedDeque的addAll(Collection col)，它以col作为参数，其中col是元素(列表，数组列表，链接列表等)的集合。整个集合会被追加或添加到出队的末尾。如果将Collection附加到双端队列，则此方法就像add()方法将返回true。

用法:

public boolean addAll(Collection c)

参数：该函数接受参数col，该参数是要添加的元素的集合。

返回值：此方法返回一个布尔值，说明是否将Collection附加到Deque。

异常：此方法接受两个异常：

NullPointerException ：如果集合中存在的任何元素为null或集合为null。
IllegalArgumentException：如果传递的集合本身是现有双端队列。

以下示例说明了addAll()方法：

范例1：将数字集合添加到ConcurrentLinkedDeque的第一个集合中

// Java program to illustrate addAll() method 
  
import java.util.concurrent.ConcurrentLinkedDeque; 
  
public class Example1 { 
    public static void main(String[] args) 
    { 
  
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<Integer> ld1 
            = new ConcurrentLinkedDeque<Integer>(); 
  
        // Add elements 
        ld1.add(1); 
        ld1.add(2); 
        ld1.add(3); 
        ld1.add(4); 
  
        // print ld1 
        System.out.println("LD1: " + ld1); 
  
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<Integer> ld2 
            = new ConcurrentLinkedDeque<Integer>(); 
  
        ld2.add(8); 
        ld2.add(1); 
        ld2.add(3); 
        ld2.add(5); 
  
        // print ld2 
        System.out.println("LD2: " + ld2); 
  
        // Adding elements of ld2 to ld1 at its end. 
        ld1.addAll(ld2); 
  
        System.out.println("After adding the ld2 to ld1: "
                           + ld1); 
    } 
}

输出：

LD1: [1, 2, 3, 4]
LD2: [8, 1, 3, 5]
After adding the ld2 to ld1: [1, 2, 3, 4, 8, 1, 3, 5]

范例2：显示IllegalArgumentException

// Java program to illustrate addAll() method 
  
import java.util.concurrent.ConcurrentLinkedDeque; 
  
public class Example2 { 
    public static void main(String[] args) 
    { 
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<String> ld1 
            = new ConcurrentLinkedDeque<String>(); 
  
        // Add elements 
        ld1.add("John"); 
        ld1.add("Johnathan"); 
        ld1.add("Jones"); 
        ld1.add("James"); 
  
        // print ld1 
        System.out.println("LD1: " + ld1); 
  
        try { 
            ld1.addAll(ld1); 
        } 
        catch (IllegalArgumentException e) { 
            System.out.println("Exception thrown while "
                               + "adding deque to "
                               + "itself is: "
                               + e); 
        } 
    } 
}

输出：

LD1: [John, Johnathan, Jones, James]
Exception thrown while adding deque to itself is: java.lang.IllegalArgumentException

范例3：显示NullPointerException

// Java program to illustrate addAll() method 
  
import java.util.concurrent.ConcurrentLinkedDeque; 
  
public class Example3 { 
    public static void main(String[] args) 
    { 
  
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<String> ld1 
            = new ConcurrentLinkedDeque<String>(); 
  
        // Add elements 
        ld1.add("John"); 
        ld1.add("Johnathan"); 
        ld1.add("Jones"); 
        ld1.add("James"); 
  
        // print ld1 
        System.out.println("LD1: " + ld1); 
  
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<String> ld2 = null; 
  
        // print ld2 
        System.out.println("LD2: " + ld2); 
  
        try { 
  
            System.out.println("After adding the ld2 to ld1: "); 
            ld2.addAll(ld1); 
        } 
        catch (NullPointerException e) { 
            System.out.println(e); 
        } 
    } 
}

输出：

LD1: [John, Johnathan, Jones, James]
LD2: null
After adding the ld2 to ld1: 
java.lang.NullPointerException

参考： https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html

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注：本文由纯净天空筛选整理自JaniceShah大神的英文原创作品 ConcurrentLinkedDeque addAll() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。